[10.x] Adds start and end string replacement helpers

[joedixon]

I've run into this issue a couple of times recently where I need to trim or replace a value from the start or end of a string.

For example, let’s assume our string is /path/to/my/public/nested/public and I want to remove /public from the end of the string. I can do:

Str::replaceLast('/public', '', '/path/to/my/public/nested/public');

// /path/to/my/public/nested

This works fine until I pass a string which no longer has /public on the end and suddenly, the /public is removed from the middle of my string:

Str::replaceLast('/public', '', '/path/to/my/public/nested');

// /path/to/my/nested

Of course, I can get around this, but it feels kinda cumbersome:

if (Str::endsWith('/path/to/my/public/nested/public', '/public')) {
    Str::replaceLast('/public', '', '/path/to/my/public/nested');
}

// /path/to/my/public/nested

This PR combines this approach into four new string helpers

Str::replaceEnd('/public', '/private', '/path/to/my/public/nested/public');
// /path/to/my/public/nested/private

Str::replaceStart('/public', '/private', '/public/path/to/my/public/nested/public');
// /private/path/to/my/public/nested/public

Str::pruneEnd('/path/to/my/public/nested/public', '/public');
// /path/to/my/public/nested

Str::pruneStart('/public/path/to/my/public/nested/public', '/public');
// /path/to/my/public/nested/public

In each end method, the replacement is only carried out if the given value exists at the end of the string. It only replaces the last occurrence.

In each start method, the replacement is only carried out if the given value exists at the start of the string. It only replaces the first occurrence.

In both cases, the prune method wraps the replace counterpart as sugar to prevent the need to pass the empty string.

[timacdonald]

Love this.